Studies of blood gas and lung histopathology were done in 10 dogs after intrapericardial aortoright pulmonaty arterial anastomosis with proximal ligation of the right pulmonary antery.
Among the 5 expired during or after operation, in 3 cases, the causes of the death were due to surgical bleeding and, in 2 cases, acute cardiopulmonary insufficiency because of large anastomosis stoma measured respectively 7mm and 10mm.
In the 5 of survivals, one was sacrificed because of empyema at postoperative 7 days and 2 were at postoperative one month and remained 2 at postoperative 3 month respectively.
The following observations were made.
1. In every survival, continuous machinary murmur was auscultated and the angiograms of all long term survivals showed the good patency of the anastomosis stoma.
2. After the ligation of the right pulmonary artery, the values of P0₂ and PCO₂ in arterial and venous blood were generally decreased comparing with the preoperative values. The mean value of P_(a)O₂ noted 83.3±11.875(p<0.01).
After the shunts operation with ligation of the right pulmonary artery, the immediate values of PH, PO₂ and PCO₂ showed no significant changes comparing with that of right pulmonary artery ligation only.
In the cases of survivals more than one month, the values of PO₂ and PCO₂ in the arterial and venous blood were generally higher than that of ligation of the right pulmonary artery only. The P_(a)O₂ value noted 103.750±7.395(p<0.01). The mean values of P_(a)O₂, PCO₂ and PH in the arterial and venous blood almost returned to that of preoperative studies.
3. In the specimens of lung from the cadavors expired due to acute cardiopulmonary insufficiency after the operation, there were massive congestion, hemorrhage in the alveolar spaces and bronchioles.
In specimens obtained at postoperative one month, there were dilatation of alveolar spaces with partial rupture, slight congestion, and alveolar wall thickening in the lung parenchyma, but there was no significant changes in pulmonary vasculature except dilation of pulmonary capillaries.
In the specimens obtained at postoperative three months, the alveolar walls were more thickened in the lung parenchyme than the finding of the specimens obtained at postoperative one month. In the wall of pulmonary capillaries, there was only slight thickening with connective tissue proliferation.
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